The KWA KM4 SR7, is a special M4 model designed for the US Navy’s elite commandos is available at GM Tático in Brazil. It has a short barrel like the KWA KM4 CQB, so it can be used for skirmishing in tight spaces. The 7″ rail system lets you attach different accessories like grips and lights. It’s made of metal alloy and has a reliable 2GX gearbox for durability and power. The KM4 SR7 is a versatile weapon that can handle any situation with agility and speed.

Another howto video courtesy of Airsoft Outlet Northwest and covers MadBull Airsoft's Blue Bucking Installation... "In this video Airsoft Outlet NW's head tech demonstrates how to install a Madbull Blue Bucking in a KWA SR7's Hop-up Unit, as well as how to modify the Hop-up adjustment dial so that it stays in place more effectively.